#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define MAXLINE     1024

int main(int argc, char *argv[])
{
    int n, int1, int2;
    char line[MAXLINE];

    while ((n = read(STDIN_FILENO, line, MAXLINE)) > 0)
    {
        line[n] = 0;        /* null terminate */
        if (sscanf(line, "%d,%d", &int1, &int2) == 2)
        {
            sprintf(line, "%d\n", int1+int2);
            n = strlen(line);
            if (write(STDOUT_FILENO, line, n) != n)
            {
                perror("write error");
                exit(0);
            }
        }
        else
            if (write(STDOUT_FILENO, "invalid args\n", 13) != 13)
            {
                perror("write error");
                exit(0);
            }
    }

    return 0;
}
